The invention relates to a fuel tank having a filling pipe arranged on a tank chamber, it being possible for the filling pipe to be separated from the tank chamber and to be reconnected thereto.
Fuel tanks of this type are frequently used in today""s motor vehicles and are known in practice. The filling pipe of the fuel tank known in practice is connected to the tank chamber via a shaped tubing. For maintenance, for example, of components of a fuel conveying unit which are arranged in the tank chamber, after the shaped tubing is detached the tank chamber can be removed separately from the filling pipe. The separation of the tank base from the filling pipe, which is generally configured such that it is very protruding, has the advantage that when the tank chamber is removed, complicated removal, for example of the rear axle of the motor vehicle, can generally be avoided. A disadvantage of the known fuel tank is that fuel vapors can pass through the point where the shaped tubing is connected to the filling pipe and the tank chamber and into the environment.
The invention is based on the problem of configuring a fuel tank of the type mentioned at the beginning in such a manner that it largely prevents fuel vapors from escaping into the environment.
According to the invention, this problem is solved by the tank chamber and the filling pipe being manufactured or welded as a single piece, and by the unit comprising the filling pipe and tank chamber having a section, which is provided for the separation, and by being configured in the regions adjacent to said section for the attachment of a connecting part.
This configuration means that the fuel tank according to the invention does not have any points of connection between the tank chamber and the filling pipe in the novel state. However, the connection of the unit comprising the tank chamber and filling pipe can be separated, for maintenance of the fuel tank according to the invention, and the tank chamber can be removed easily. The components are subsequently connected to one another by means of a connecting part. In the novel state of the fuel tank escape of fuel from the fuel tank is reliably avoided. In the unlikely case of maintenance being carried out, the fuel tank according to the invention, like the known fuel tank, has sealing points on the connecting part. By this means, escape of fuel from the fuel tank according to the invention is largely avoided. The manufacture of the tank chamber together with the filling pipe as a single piece can take place by them being manufactured in a common mold or by welding or bonding.
According to another advantageous development of the invention, a compensation of tolerance between the separated regions can be achieved in a simple manner if the connecting part is designed as a piece of tubing.
According to an advantageous development of the invention, the unit comprising the filling pipe and tank chamber can be separated in a simple manner if the unit comprising the filling pipe and tank chamber has a circumferential groove in the section provided for the separation. A further advantage of this configuration resides in the fact that the groove serves as a marking and therefore reduces the risk of erroneous separation which may then result in an erroneous fit of the connecting part.
According to another advantageous development of the invention, reliable retention of the connecting part can be ensured in a simple manner if the unit comprising the filling pipe and tank chamber has, on its outside, circumferential, radially protruding projections for the attachment of the connecting part. The seal-tightness of the fuel tank is also increased by means of the projection.
According to another advantageous development of the invention, a collision of ends produced by separating the unit comprising the filling pipe and tank chamber can be reliably avoided if the unit comprising the filling pipe and tank chamber has two spaced apart points of separation, and if the points of separation are each adjacent, on their sides facing away from each other, to a region provided for the attachment of the connecting part. By this means, the connecting part spans a region separated from the fuel tank and serves as a spacer and as a means of compensating for tolerance between the points of separation.
According to another advantageous development of the invention, a compensation for tolerance between the tank chamber and the filling pipe can be produced in a simple manner by the unit comprising the filling pipe and tank chamber having a bellows in the region provided for the separation.
According to another advantageous development of the invention, an arrangement of a series of elastic means provided for compensating tolerances can be avoided if the bellows is arranged between two regions provided for the attachment of the connecting part. The fuel tank thereby first of all has the bellows as a means for compensating for tolerance. In the event of maintenance, the bellows is removed and replaced by the connecting part.
According to another advantageous development of the invention, the connection of the region spanned by the connecting part is able to absorb particularly high tensile forces if the regions provided for the attachment of the connecting part have a circumferential bead, and if the connecting part is designed as a shaped tubing of a configuration corresponding to the beads.
The invention permits numerous embodiments. To further clarify its basic principle two of these are illustrated in the drawing and are described below. In the drawings.